New Paradigm of Evidence-Based Nutrition

A Commentary on the Nutrient-Chronic Disease Relationship and the New Paradigm of Evidence-Based Nutrition

A discussion regarding the relationship between predisposition to many chronic diseases and the diet, nutritional status, and lifestyle of an individual.

Continued from Yesterday

Evidence-Based Medicine Vs. Evidence-Based Nutrition

Unlike pharmaceuticals, which have long been studied under the principles of EBM, nutrition and chronic disease research is in a relative state of infancy. Nutrition researchers have yet to establish clear criteria and guidelines for how best to study the effects of nutrients in humans, and subsequently how to evaluate those findings—in other words, what constitutes evidencebased nutrition (EBN).

In the absence of such guidelines, the long-established principles of EBM and its strong reliance on randomized, controlled trials (RCTs) have been applied to fill this void (Figure 1). Within this paradigm, expert opinion is given the least weight, while practitioners’ clinical experiences are not even considered part of the evidence base.

The traditional RCT is viewed in the EBM hierarchy as the gold standard for research on cause-and-effect relationships, and its design has been more suited to assess the efficacy and safety of drugs, not nutrients. When designed, executed, and analyzed properly, the results of RCTs can be persuasive and provide a high level of certainty.

Such certainty, one could argue, is necessary when assessing the effects of expensive, potent, and potentially dangerous drug therapies. This cost-benefit-risk equation,while appropriate for drugs, is substantially different for nutrients. Several nutrition researchers have, in recent years, raised concerns over what is perceived to be the misapplication of drug-based trials to assess nutrition questions, without taking into account the totality of the evidence or the complexitiesand nuances of nutrition.5–8

Drugs tend generally to have single, targeted effects; drugs are not homeostatically controlled by the body and can easily be contrasted with a true “placebo” group; drugs can act within a relatively short therapeutic window of time, often with large effect sizes. In contrast, nutrients tend to work in complex systems in concert with other nutrients and affect multiple cells and organs; nutrients are homeostatically controlled, and thus the body’s baseline nutrient “status” affects the response to a nutrient intervention; a nutrient intervention group cannot be contrasted with a true placebo group (ie, “zero”exposure group); and with respect to chronic disease prevention,nutrient effect sizes tend to be small and may take decades to manifest. Finally, the very absence (or inadequacy) of a given nutrient produces disease, which is a fundamental differencecompared to drugs (summarized in Table 1).

Continued Tomorrow

http://www.naturalmedicinejournal.com/article_content.asp?article=117

http://www.depsyl.com/

http://back2basicnutrition.com/

http://bionutritionalresearch.olhblogspace.com